Pressure-fluid tool.



G. H, GELA/IAN.

Patented Aug. 14, 1917.

Y Legame.

GEORGE H. GILMAN, OF CLAREMONT, NEW' HAMPSHIRE, ASSIGNOR TO SULLIVAN MACHINERY COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

PRESSURE-FLUID TOOL.

Specication of Letters Patent.

Patented Aug. 1d, 1917.

Original application filed. April 22, 1908, Serial No. 428,618. Divided and this application led December 21.,

1916. Serial No. 138,186.

To all whom t may concern:

Be it known that I, GEORGE H. GILMAN, a citizen of the United States, and a resident of Claremont, county of Sullivan, and State of New Hampshire, have invented an Tm-` provement in Pressure-Fluid Tools, of which the following description', in connection with the accompanying` drawings, is a specification, like characters on the drawings representing like parts.

My invention relates to pressure fluid tools adapted to be operated by compressed air or other elastic pressure fluid, being more particularly concerned with the provision of simplified and efficient valve controlling means therefor. This application is a division of my prior pending application, Serial No. 428,618, filed April 22, 1908.

My invention will be best understood by reference to the following description, when taken in connection with the accompanying illustration of one specific embodiment thereof, while its scope will be more particularly pointed out in the appended claims.

In the drawings:

Figure 1 is a longitudinal central section taken through a pneumatic hammer embodying one form of my invention; and

Fig. 2 is a similar sectional view taken in a plane at right angles to the plane of the section shown in Fig. 1.

Referring to the drawings, and to the embodiment of my invention which is illustrated therein, there is provided a cylinder 1, the rear or upper end' (Fig. 1) of which has threaded engagement with a hollow cas-y ing 2, the latter having a closed end and acting as a housing for the rear end of the cylinder and a valve block 3. The cylinder is prevented from accidental unscrewing by a split clamping collar L1. A portion of a handle piece 5, or other member by which the tool is supported is shown, but it will be understood that the particular construction of handle forms no material part of this invention, and that the same may be used with various handles or other supports well-known in the art.

The u per end of the cylinder chamber is closed y a plate 6, which is held between the valve block and the cylinder end, and there is provided a valve block covering or cap 7, between the rear or upper end of the valve block and the walls of the casing 2.

The cylinder, Valve block and plate, are maintained in the alinement required for the registration of their connecting passages by means of a dowel pin 8. The head of the casing is recessed at 9 to provide a constant pressure supply chamber, to which, when the tool is in use, compressed air or other pressure fluid is constantly supplied through an air inlet 10.

The valve block is of generally cylindrical shape, and has an' interiorly formed valve chamber axially alined with the cyl inder, the valve chamber having a forward portionv 11 of larger diameter, and a rear portion 12 of contracted diameter, in which the valve is arranged to move. The valve is of the piston type, having a head 14 of reduced diameter, which moves within the smaller chamber 12, and an oppositely arranged head 15 of larger diameter, which moves in the chamber 11. Between the smaller head 111 and the larger head 15, there is provided an exterior annular valve groove 16 of somewhat lesser diameter than the diameter of the chamber 12, and about the larger head l'there is also provided an annular valve groove 17.

Live pressure Huid is constantly admitted from the constant pressure chamber 9 to the upper end of the enlarged portion 11 of' the valve chamber, and against apressure area 18, which latter is'provided by the shoulder formed between the head 15 and the annular groove 16. This admission of live pressure takes place through one' or more passages 19, the latter extending longitudinally through the cap or cover 7 and the valve block, and opening into the chamber 11, within the circumferential limits of the chamber and the shouldered portion 18. Acting against the area 18 of the valve, the admitted pressure fluid exerts a constant tendency to force the valve forward into the position shown in Fig. 2, in which position, the upper area or edge 18 of the head 15 has passed below and uncovered an annular groove 20 formed in the enlarged portion of the valve chamber and connecting with one or more passages 21, the latter leading forward through the valve block and the plate 6 into the upper 01 rear end of the cylinder. In the forward position of the valve, therefore, as represented in Fig. 2, pressure fluid is being admitted to the sov Near the close of the forward movement of the pistomth'e controlling valveY is reversed by the admission of pressure `fluid to the forward end-ofthe enlargedportion 11 of theV valve chamber, which fluid acting against'the larger pressure area -of'the valve A at that end acts to reverse the valve against the constantpressure upon thel smaller pressure area 18.` In the illustrated'form of myl invention, in order Vto reduce the weight of the valve, the latter is cored or hollowed out, andto reduce the resultant clearance, the plate 6 is provided with a rearwardly extending plug 23, which nearly but not quite fills-the cored portion of the valve in, its forward position.

Pressure llui-dis-admitted against the enlarged forward end of the valve, and to the lower end of the chamber 11, through an intermittent pressure passage 24, which opens into the valve chamber through a radial or lateral passage 25, and into the cylinder through a port 26, and also through a second and more advanced port 27. Y

The intermittent pressure passage is placed in communication with a constant pressure passage 28, which latter opens into the cylinder through a port 29 `by means of a circumferential groove 30 formed in the piston.'` When the rcircumferential groove uncovers the ports 29 and 26, pressure fluid is admitted to the lower end of the valve chamber to raise the valve. The constant pressurepassage 28 is connected at the rear end of the valve block by a lateral passage 31, with one of the longitudinal pressure passages 19, as represented in Fig. 1'.

In the reverse or rearward position of the valve F ig. v1), the annular chamber groove 20, and therefore the rear end of 'the cylinder, is opened to the exhaust through the annular valve groove 17, which on the rearward movement' of the valve, causes cominunication between the chamber groove and one or more radial exhaust ports 32 leading from the valve chamber laterally through the valveblock. The valve chamber is surrounded by an annular space or chamber 33, betweenlthe valve block and the housing or casing 2, and the latter is perforated at vone or more points, such as 34 and 35, so as to permit free exhaust of pressure fluid to the `atmosphere through the port or ports 32.

In the rearward or return movement of the piston, pressure fluid is admitted to the forward end of the cylinder through a passage 3G opening into the cylinder through a port 37, the latter being located near the forward end ofthe cylinder. The passage 36 extends longitudinally of the walls of thecylinder, and the valve block, and is connected with 4the upper end of the reduced portion112 of the valve chamber by a lateral or radial port 38.

In the rearward position of the valve (Fig. 1), the lateral port 38 is opened to the annular valve groove 1,`so that pressure liuid which is admitted constantly to and about said groove passes through the port 38,

passage 36 and port 37, to the forward` end of the cylinder, to return the piston.

The piston has ua reduced portion 39 having aslidin-g t within contractedwalls 40 of the cylinder, the effective area `against which the pressure acts in returning the piston being provided by the shoulderformed between the contracted portion and the main pressure fluid from the larger area of the,

valve, since the forward intermittent pressure port 27 is then uncovered by the piston, and therefore also open to the exhaust through the passage 43.

The withdrawal of pressure Huid from the larger area of the valvecauses the reversal of thevalve again from the position shown in Fig. 1 to that shown in Fig. 2, this, in turn, admitting pressurerfluid to the rear end-of the cylinder through the passage 21 and the circumferential chamber groove20, as previously described.

During the subsequent forward movement of the piston, after the reduced piston portion 39 enters the contracted cylinder walls 40, pressure fluid continues to be exhausted from the forward end of the piston prior to the reversal of thevalve, through the port 37, the return passage 36 and the port 38, which latter on the forward` movement of the valve is uncovered by the smaller valve head 14, and thereby opened to the rearmost end of the valve chamber. The latter is at all times open to the `exhaust through a lateral exhaust port 44, formed in the valve block cap 7 (Fig. 2), andconnecting the end 12 of the valve chamber with the annular exhaust chamber 33.? p

By bringing the pressure fluid supply passages 19 into thechamber. portion 11, within its circumferential limits, no groove 4need bc cut in the chamber to receive them, and the fluid is saved making the additional half turn in reaching the rear end of the cylinder.

While I have shown and described in detail one specific embodiment of my invention, it is to be understood that the same is not limited to the details shown or the construction or relative arrangement of the parts disclosed, but that extensive modifications may be made therefrom without departing from the spirit of my invention.

Having thus described one specific embodiment of my invention, what I claim and desire to secure by Letters Patent is l. A pressure-fluid tool having a differential valve provided with two heads of different diameters and an intervening annular groove, said valve being located in a valve chamber, the latter having a contracted portion and an enlarged portion to correspond to the two diameters of the valve, one or more pressure fluid supply passages opening into one end of the enlarged portion of the valve chamber within its circumferential limits, a passage leading to the rear end of the cylinder adapted to be placed in communication withsaid supply passage or passages in one position of the valve, and a passage leading to the forward end of the cylinder and connected with said passages in the reverse position of the valve.

2. A pressure-fluid tool having a cylinder, a valve block at the rear of the cylinder, a pressure actuated, differential valve provided vvith two heads of different diameters, the head of the smaller diameter being at the rear of the valve block, a valve chamber having a contracted portion in which the smaller head moves, an exhaust passage connected with said contracted chamber portion, a passage leading to the forward end of the cylinder and opening into said contracted chamber portion and adapted to be placed in communication with the exhaust in the forward position of the valve, a valve chamber portion of larger diameter having one or more inlet passages communicating therewith leading to the rear end of the cylinder, an exhaust passage also communicating with said valve chamber portion of larger diameter and adapted to be placed in communication with said inlet passages in the rearward position of the valve, and one or more supply passages opening into the rear end of said enlarged chamber portion and within the circumferential limits of tlm` valve head of larger diameter, said supply passages being connected with the said inlet passages in the forward position of the valve.

3. A pressurediuid tool having a differential, pressureactuated valve provided with diierential pressure areas, a shouldered portion upon said valve constituting one of said areas, a valve chamber-portion in the end of which said shouldered portion moves, and one or more pressure supply passages opening into the end of said chamber-portion within circumferential limits of the shouldered portion of said valve.

In testimony whereof, I have signed my name to this specication.

` GEORGE I-I. GILMAN.

Copies of this patent may be 'obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

